import java.util.ArrayList;
import java.util.Scanner;

/**
 * Creat with IntelliJ IDEA
 * Description:
 * User:WZW
 * Date:2021-11-27
 * Time:20:00
 */
public class TestDemo {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNextLine()){
            String string = scanner.nextLine();
            char[] chars = string.toCharArray();
            ArrayList<Character> characters = new ArrayList<>();
            int size = chars.length;
            for (int i = 0; i <size ; i++) {
                if(!characters.contains(chars[i])){
                    characters.add(chars[i]);
                }
            }
            for (char c:characters) {
                System.out.print(c);
            }
            System.out.println();
        }
    }
}
